static char help[] = "Check if DMClone for DMNetwork Correctly Shallow Clones Topology Only \n\n";

#include <petscdmnetwork.h>

/*
CreateStarGraphEdgeList - Create a k-Star Graph Edgelist on current processor
  Not Collective

  Input Parameters:
. k    - order of the star graph (number of edges)
. directin - if true direction of edges is towards the center vertex, otherwise they are directed out of the center vertex.

  Output Parameters:
.  ne - number of edges of this star graph
.  edgelist - list of edges for this star graph, this is a one dimensional array with pairs of entries being the two vertices (in global numbering of the vertices) of each edge,
              [first vertex of first edge, second vertex of first edge, first vertex of second edge, second vertex of second edge, etc].

              User is responsible for deallocating this memory.
*/
PetscErrorCode CreateStarGraphEdgeList(PetscInt k,PetscBool directin, PetscInt *ne, PetscInt *edgelist[])
{
  PetscInt i;

  PetscFunctionBegin;
  *ne = k;
  PetscCall(PetscCalloc1(2*k,edgelist));

  if (directin) {
    for (i=0; i<k; i++) {
      (*edgelist)[2*i]   = i+1;
      (*edgelist)[2*i+1] = 0;
    }
  } else {
    for (i=0; i<k; i++) {
      (*edgelist)[2*i]   = 0;
      (*edgelist)[2*i+1] = i+1;
    }
  }
  PetscFunctionReturn(0);
}

/*
CreateSimpleStarGraph - Create a Distributed k-Star Graph DMNetwork with a single PetscInt component on
all edges and vertices, aselectable number of dofs on vertices and edges. Intended mostly to be used for testing purposes.

  Input Parameters:
. comm       - the communicator of the dm
. numdofvert - number of degrees of freedom (dofs) on vertices
. numdofedge - number of degrees of freedom (dofs) on edges
. k          - order of the star graph (number of edges)
. directin   - if true direction of edges is towards the center vertex, otherwise they are directed out of the center vertex

  Output Parameters:
. newdm       - The created and distributed simple Star Graph
*/
PetscErrorCode CreateSimpleStarGraph(MPI_Comm comm, PetscInt numdofvert, PetscInt numdofedge, PetscInt k, PetscBool directin, DM *newdm)
{
  DM             dm;
  PetscMPIInt    rank;
  PetscInt       ne = 0,compkey,eStart,eEnd,vStart,vEnd,e,v;
  PetscInt       *edgelist = NULL,*compedge,*compvert;

  PetscFunctionBegin;
  PetscCall(DMNetworkCreate(comm,&dm));
  PetscCall(DMNetworkSetNumSubNetworks(dm,PETSC_DECIDE,1));
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  if (rank == 0) {
    PetscCall(CreateStarGraphEdgeList(k,directin,&ne,&edgelist));
  }
  PetscCall(DMNetworkAddSubnetwork(dm,"Main",ne,edgelist,NULL));
  PetscCall(DMNetworkRegisterComponent(dm,"dummy",sizeof(PetscInt),&compkey));
  PetscCall(DMNetworkLayoutSetUp(dm));
  PetscCall(PetscFree(edgelist));
  PetscCall(DMNetworkGetEdgeRange(dm,&eStart,&eEnd));
  PetscCall(DMNetworkGetVertexRange(dm,&vStart,&vEnd));
  PetscCall(PetscMalloc2(eEnd-eStart,&compedge,vEnd-vStart,&compvert));
  for (e=eStart; e<eEnd; e++) {
    compedge[e-eStart] = e;
    PetscCall(DMNetworkAddComponent(dm,e,compkey,&compedge[e-eStart],numdofedge));
  }
  for (v=vStart; v<vEnd; v++) {
    compvert[v-vStart] = v;
    PetscCall(DMNetworkAddComponent(dm,v,compkey,&compvert[v-vStart],numdofvert));
  }
  PetscCall(DMSetFromOptions(dm));
  PetscCall(DMViewFromOptions(dm, NULL, "-dm_view"));
  PetscCall(DMSetUp(dm));
  PetscCall(PetscFree2(compedge,compvert));
  PetscCall(DMNetworkDistribute(&dm,0));
  *newdm = dm;
  PetscFunctionReturn(0);
}

int main(int argc, char **argv)
{
  DM             dm, dmclone,plex;
  PetscInt       e,eStart,eEnd,ndofs,ndofsprev;
  PetscInt       *compprev,*comp,compkey;
  PetscInt       dofv=1,dofe=1,ne=1;
  PetscSection   sec;
  Vec            vec;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  /* create a distributed k-Star graph DMNetwork */
  PetscCall(PetscOptionsGetInt(NULL,NULL,"-dofv",&dofv,NULL));
  PetscCall(PetscOptionsGetInt(NULL,NULL,"-dofe",&dofe,NULL));
  PetscCall(PetscOptionsGetInt(NULL,NULL,"-ne",&ne,NULL));
  PetscCall(CreateSimpleStarGraph(PETSC_COMM_WORLD,dofv,dofe,ne,PETSC_TRUE,&dm));
  PetscCall(DMNetworkGetEdgeRange(dm,&eStart,&eEnd));

  /* check if cloning changed any componenent */
  if (eStart < eEnd) {
    PetscCall(DMNetworkGetComponent(dm,eStart,0,NULL,(void**)&compprev,&ndofsprev));
  }
  PetscCall(DMClone(dm,&dmclone));
  if (eStart < eEnd) {
    PetscCall(DMNetworkGetComponent(dm,eStart,0,NULL,(void**)&comp,&ndofs));
    PetscCheck(*comp == *compprev,PETSC_COMM_WORLD,PETSC_ERR_PLIB,"Cloning changed the Original, comp (previous) : %" PetscInt_FMT " comp (now) : %" PetscInt_FMT,*compprev,*comp);
    PetscCheck(ndofsprev == ndofs,PETSC_COMM_WORLD,PETSC_ERR_PLIB,"Cloning changed the Original, ndofs (previous) : %" PetscInt_FMT " ndofs (now) : %" PetscInt_FMT,ndofsprev,ndofs);
  }

  /* register new components to the clone and add a dummy component to every point */
  PetscCall(DMNetworkRegisterComponent(dmclone,"dummyclone",sizeof(PetscInt),&compkey));
  PetscCall(DMNetworkGetEdgeRange(dmclone,&eStart,&eEnd));
  PetscCall(PetscMalloc1(eEnd-eStart,&comp));
  for (e=eStart; e<eEnd; e++) {
    comp[e-eStart] = e;
    PetscCall(DMNetworkAddComponent(dmclone,e,compkey,&comp[e-eStart],2));
  }
  PetscCall(DMNetworkFinalizeComponents(dmclone));
  PetscCall(PetscFree(comp));

  PetscCall(PetscPrintf(PETSC_COMM_WORLD," dm: \n"));
  PetscCall(DMView(dm,PETSC_VIEWER_STDOUT_WORLD));
  PetscCall(DMNetworkGetPlex(dm,&plex));
  PetscCall(DMGetLocalSection(plex,&sec));
  PetscCall(PetscSectionView(sec,PETSC_VIEWER_STDOUT_WORLD));

  PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n dmclone: \n"));
  PetscCall(DMView(dmclone,PETSC_VIEWER_STDOUT_WORLD));
  PetscCall(DMNetworkGetPlex(dmclone,&plex));
  PetscCall(DMGetLocalSection(plex,&sec));
  PetscCall(PetscSectionView(sec,PETSC_VIEWER_STDOUT_WORLD));

  /* create Vectors */
  PetscCall(DMCreateGlobalVector(dm,&vec));
  PetscCall(VecSet(vec,1.0));
  PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n dm vec:\n"));
  PetscCall(VecView(vec,PETSC_VIEWER_STDOUT_WORLD));
  PetscCall(VecDestroy(&vec));

  PetscCall(DMCreateGlobalVector(dmclone,&vec));
  PetscCall(VecSet(vec,2.0));
  PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n dmclone vec:\n"));
  PetscCall(VecView(vec,PETSC_VIEWER_STDOUT_WORLD));
  PetscCall(VecDestroy(&vec));

  PetscCall(DMDestroy(&dm));
  PetscCall(DMDestroy(&dmclone));
  PetscCall(PetscFinalize());
}

/*TEST

  test:
    suffix: 0
    args:

  test:
    suffix: 1
    nsize: 2
    args: -dofv 2 -dofe 2 -ne 2

 TEST*/